CNC-pen-plotter

A multi axes (XY) CNC pen plotter machine.

1. Introduction

The following repository holds the code, schematics and hardware needed to build a simple two linear axes plotter controlled with an Arduino and a CNC shield.

The X axis is controlled by two Nema 17 stepper motors and the Y axis is controlled by another Nema 17 stepper motor.

The commands are sent via the “Universal GCode sender” and the GCode can be generated using any slicer/CAM software (Inkscape, Fusion360,...).

2. Preparation

2.1. Hardware

The assembly process is quite straightforward:

1. Assembly the pulleys and pulley holders (3 in total).
2. Assembly the pulleys, the motors and the motor holders (3 in total).
3. Assembly the X shafts and the X shaft holders (2 in total).
4. Assembly the movable left side base.

5. Assembly the movable right side base.

6. Assembly the movable middle base.

7. Assembly all the bases and shafts accordingly.

8. Place the belts and make sure to tighten them up.
9. Manually move the X and Y bases to check for uneven movements or noises. Try loosing/tightening the screws and adjusting the different elements to make the movements as smooth as possible.

2.2. Electronics

Before proceeding with the electronics, I really recommend checking that all the components work properly. Pay special attention to A4988 modules, as they need to be tuned before being used. Find a nice tutorial about tuning them here.

After ensuring that all the components work properly follow next diagram to setup your electronics. Don't forget to connect the X.STEPS/DIR pins so the commands in the A axis are the same as the ones in the X axis (remember that the X direction is controlled by two motors!).

2.3. Software

Install the GRBL into your Arduino. Find here some useful instructions on how to do this.

• Download and install Universal Gcode Sender for sending Gcode commands to the Arduino.
• Open Universal Gcode Sender and connect to the Arduino.

3. Setting up

Before drawing anything, we will need to check that everything is working correctly. In order to do that, please follow next steps:

1. Disconnect all the belts.
2. Test each motor’s rotation direction by sending the G0 X0 or G0 Y0 command. Change the wiring (WITHOUT power!) if needed to make sure the motors work as intended.
3. Place the belts once more and make sure to tighten them up.
4. Repeat the 2 step to make sure all the components work properly with the belts installed.
5. If microstepping was enabled, you will need to adjust the step/mm relation of each axis. This is a straighforward process, so follow this.
6. Congratulations!!!! You are ready to start drawing!!!

4. Drawing

Now that everything is ready, it is time to have some fun:

1. Generate a Gcode from any software you like (For beginners, you can start with Inkscape).
2. Open "Universal Gcode Sender" and connect to your arduino.
3. Open the Gcode you just created.
4. Press RUN and see the machine do its magic!!!!!

5. Requirements

5.1. Software

You should install/have the following software in order to control your CNC machine:

• Universal Gcode Sender
• Arduino IDE
• Inkscape*
• StippleGen*

*(Not necessary but recommended)

5.2. Components

In order to construct this project, you will need the following components:

• Microcontroller: Arduino UNO
• CNC shield: CNC shield V3.0
• Stepper motor driver: A4988
• Power supply: Voltage: 12V Amperage: 5A
• Pulley: Geared pulleys: 5mm, 20 teeth
• Transmission belt: GT2, 5mm
• Linear bearings: 8mm
• Shafts: 8mm, 500mm (2 pcs) and 250mm (2 pcs)
• Shaft holders: 8mm
• Fan: 12V